Itinerant scenario for Fe-pnictides: comparison with quantum Monte Carlo

TL;DR

This paper compares the itinerant scenario for Fe-based superconductors with unbiased Quantum Monte Carlo results, showing that the itinerant approach accurately captures the hierarchy of instabilities observed in QMC simulations.

Contribution

The study demonstrates that the itinerant scenario's predictions align with QMC results, validating its applicability to Fe-based superconductors.

Findings

Itinerant scenario matches QMC hierarchy of instabilities.

Orbital order types differ between QMC and previous itinerant analyses.

Results support the validity of the itinerant approach for these materials.

Abstract

Recent applications of Quantum Monte Carlo (QMC) technique to Fe-based superconductors opened a way to directly verify the applicability of the itinerant scenario for these systems. Fe-based superconductors undergo various instabilities upon lowering temperature (magnetism, superconductivity, nematicity/orbital order), and one can check whether the hierarchy of instabilities obtained within the itinerant approach is the same as in unbiased QMC simulations. In a recent paper [arXiv:1512:08523] the authors considered the simplest two-band model with interaction tailored to favor orbital order. The type of the orbital order found in QMC is different from the one found in earlier itinerant analysis. We report the results of our calculations within the itinerant scenario and argue that they are in perfect agreement with QMC.